refactor(workspace): enforce layered crate boundaries

crates/aether-provider/transport/src/claude_code/mod.rs

@@ -0,0 +1,17 @@
+mod auth;
+mod fingerprint;
+mod policy;
+mod request;
+mod url;
+
+pub use auth::supports_local_claude_code_auth;
+pub use fingerprint::{
+    generate_fingerprint, generate_random_fingerprint, header_fingerprint_from_fingerprint,
+    sanitize_fingerprint,
+};
+pub use policy::{
+    local_claude_code_transport_unsupported_reason_with_network,
+    supports_local_claude_code_transport_with_network,
+};
+pub use request::{build_claude_code_passthrough_headers, sanitize_claude_code_request_body};
+pub use url::build_claude_code_messages_url;